Hemstitch sewing-machine.



C. M. ABERCROMBIE.

HEMSTITCH SEWING MACHINE.

APPLICATION min :uur 24.1915.

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HEMSTITCH SEWING MACHINE.

APPLICAUUN FILED luLY 24. nels.

1 ,27 1 ,256. Patented July 2, 1918.

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IN1/EN ma Charles L emromw ,4 TTORNEY UNTTED sTATEs PATENT oEEIoE.

CHARLES M. ABERCROMBIE, 0F BRIDGEPORT, CONNECTICUT, ASSIGNOR T0 THE SINGER MANUFACTURING COMPANY, A CORPORATION OF NEW JERSEY.

HEMSTITCH SEWING-MACHINE.

Specicatlon of Letters Patent.

Patented July 2, 1918.

Application filed July 24, 1915. Serial No. 41,658.

To all whom t may concern.'

Bc it known that I, CHARLES M. ABER- CROMBIE, citizen of the United States, residing at Bridgeport, in the county of Fairfield and State of Connecticut, have invented certain new and useful Improvements in Hemstitch Sewing-Machines, of which the following is a specification, reference being 'had therein to the accompanying drawings.

This invention relates to improvements in sewing machines, more particularly that class of machines employed for producing a hemstitch seam, and has for its object to simplify and strengthen the elements and to improve their cooperation to better meet the requirements of given products at a comparatively hi h speed in connection with factory use, t e more important feature in construction being the providing of an improved form of pitman connection for transmittin from the main-shaft verticaltly arrange movements of the needle in di erent planes.

In the accompanying drawings illustrating the invention, in the several f1 res of which like parts are similarly designated, Figure 1 is a view in elevation partly in full lines and partly in section of a hemstitch sewing machine equipped with the present improved means. Fig. 2 is a front end elevation of Fig. 1. Fig. 3 is a detail of the pitman. Fig 4 is a perspective of the pitman operating arm. Fig. 5 is a face view of the cam-gear for operating the feed-lift rock-shaft, the upper end portion of the feed-lift rock-shaft connection and the gear carried by the main-shaft or actuating said cam-gear. Fi 6 is a face View of the cam which, throng suitable connections, operates the feed rock-shaft. Figs. 7, 8, 9 and 10 are elevations of the needle-bar, the

iercer carrying tube, the needle-bar guidebracket and needle-bar yoke, respectively.

1 represents the bed-plate of the sewing machine upon which is mounted the bracketarm comprising the arm-bracket 2 and standard 3, 4 the main or needle-bar drivin shaft mounted in suitable bearings form in the bracket-arm and provided with the hand or band-wheel 5, belt-pulley 6, gear member 7 and shaft flange 8. 9 denotes the needle-thread take-up, the latter comprising an angular extension of the integrally formed ortion 10 ulcrumed on a stud 11 secured 1n the iiange 8 and carrying the integrally formed crank-arm 12 into which is threaded a stud-screw 13 upon which is fulcrumed the upper end of the needle-bar actuating link 14, and 15 an arm fulcrumed on a stud 16 secured in the head 17 of the armbracket and carrying at its opposite end a pin 18 which loosely passes through said take-up at the intersection of the portions 9 and 10. 19 denotes the spring-depressed cloth-presser carrying bar carryin the cloth-pressers as 20, and actuated to e evate the latter above the fabric by the manual manipulation of the liftin lever 21.

22 represents the needlear carrying the tubular guide 23 having the slot 24, and lugs, as 25, said tubular portion being secured on said needle-bar by screws, as 26, passing throu h one member of said lugs and threaded into the oppositely arranged member, and loosely surrounding the lower end portion of said needle-bar is a tubular piercer-carrying bar 27 rovided at its upper end with a pinch col ar 28 having a stud 29 connected with the lower end of the link 14, said piercer-carrying bar being confined between the lower end of the tubular guide 23 and the needle-carrying bracket 30 secured by screw 31 on the needle-bar, thus transmitting from the main-shaft to the needle-bar oppositely directed vertical movements and 32 denotes a piercer-carrying bracket provided with a piercer 33 and secured by screws 34 on the lower end of said piercer-carrying bar.

35 represents a yoke provided at its lower end with a lug 36 seated on the stationary wall 37 and through which the tubular ortion 27 moves vertically, the op osite en of said yoke being fulcrumed on tlrie needle-bar and held against vertical movement by the suitably secured needle-bar bushing 38. 39 denotes a guideway formed in said yoke between the walls, as 40, of which track the lugs 25, the latter, throu h the oscillatory movements of said yoke y means later to be referred to, transmitting oscillatory movements to the needlebar, thus causing the needle to be reciprocated in dilerent vertical planes.

The gear-member 7 carried by the mainshaft meshes with a gear-member 41 havin a hollow hub 42 mounted to rotate on a sha t 43 suitably secured in the bracket-arm, the ratio of said gears being as 1 to 3, the same as is common to machines of the present 110 class, and upon said hub is suitably secured a needle-bar oscillating cani 44 provided with cam-groove 45 and a feed-cam 46 provided with a cam-groove 47, the gear-member 41 being provided with a feed-lift camgroove 48 into which tracks a cam-roller 4-9 mounted upon a stud 50 suitably secured in the feed-lift connection 51, thc latter having a forked free end 52 which embraces a block 53 loosely mounted on the shaft 43 and held against accidental displacement by the screw 54 threaded in the shaft 48. The lower end of the connection 51 is pivotally connected to an arm 55 (shown in dotted lines only) carried by the feed-lift rock-shaft 56 carrying at its front end a bracket-arm 57 provided with a block 58 located in the forked opening 59 formed in the rear end of the feed-dog carrying bar 60, the opposite end of the latter having formed integral with it a cross-bar 62 (shown in dotted lines only) having its oppositely arranged ends fnl.- crumed on suitably secured pintle-screws, as 63, (shown in dotted lilies only) carried by lugs, as 64, formed integral with the feed rock-shaft 65, thus transmitting from the feed-lift cam-groove 48 oppositely arranged vertical movements to the feed-dog 66 carried by the feed-dog carrying bar 60.

67 denotes a feed rock-shaft connection pivotally connected at its lower end with the crank-arm 68 carried by the rock-shaft 65 and at its opposite end provided with a slideblock 69 adjustably secured in the guideway 70 formed in the segment-lever 71 secured at one end by screws 72 on a rock-shaft 73 mounted in suitable bearings formed in the arm-standard 3 and held against endwise movement by the suitably secured collar 74, the opposite end of said segment-lever being provided with the boss 75 into which is secured by nuts 76 a stud 77 provided with a roller 78, which latter tracks a cam-groove 47 formed in the feed-cam 46, thus transmitting from the latter feed movements to the feed-dog 66.

8O represents the loop-taker actuating shaft carrying at one end the belt-pulley 81 operatively connected by the belt 82 with the pulley 6 carried bg the main-shaft 4, the opposite end of the s aft having secured upon it a gear-member 83 which meshes with a gear-member 84 carried by the loop-taker shaft 85, said gear-members 83 and 84 being of the ratio of 2 to 1, thus giving to the looptaker shaft two rotations to one complete actuation of the needle-bar, the shaft 85 being Seated at its lower end in a suitable cupshaped bearing 86 formed in the screw 87, the opposite end of the shaft 85 carrying the loop-taker 88 (the elements 83, 84, 85, 86 and 88 being shown in dotted lines only Fig. 1).

89 represents an oseillatin pitman driving lever provided with a ulcrum-pin 90 journaled in a bushing 91 suitably secured in the bracket-arm, a collar 92 secured by screw 93 on the inner end of said pin acting to hold the same against accidental movement in the direction of its length, the oscillating lever, at its lower end, being provided with a stud 94 carrying a cam-roller 95 tracking the cam-groove 45 formed in the cam 44, thus giving to the lever 89 oscillating movements.

96 represents an oscillating pitman-lever bracket adjustably secured by screw 97 in a guideway 98 formed in the lever 89, said bracket having secured to it by cap 99, screws 100 and threaded surfaces, as 101, one end of a spiral spring 102 whose opposite end is threaded into the rigid portion 103 of the pitman and held against accidental lnovement by the collar 104 and screw 105 acting on the split portion 106 of said rigid portion, the front end of the latter being provided with a spiral spring 107 secured at one end in said stationary portion in like manner as spring 102, the opposite end of the spring 107 being operatively connected with the yoke 35 by cap 108, screws as 109 and threaded surfaces, as 110, thus transmitting from the groove 45 of the cam 44 oscillatory movements of the needle-bar about its axis, such oscillatory movements effecting, through the bracket 30 carried by the needle-bar, movements of the needle in different vertical planes. In the construction of a pitman comprising the rigid portion 103 and spiral springs 102 and 107 as herein, the springs are preferably formed with the coils of Wire in juxtaposed relationship, and the resilient strength of the springs in the direction of their length must be greater than is required for transmitting the power, so that, the springs will yield only in directions at an angle to the axis of the rigid portion.

It is evident that in transmitting power from one oscillatory driving element to a driven sliding element only that end of the rigid portion of the pitman connected with the oscillating element would require the employment offthe spring.

In the present, as in sewing machine construction for effecting a true hemstitch seam, the feed and feed-lift cam-grooves 47 and 48, respectively, are constructed and actuated to give to the fabric two feed movements forward and one return feed movement for each hemstitch figure, and the calngroove 45 in the cam 44 for giving to the needle its lateral movements is constructed and actuated to e'ect two descents of the needle in like vertical planes and one descent in a different vertical plane for each hemstitch figure.

Having thus set forth the nature of the invention, what I claim herein is 1. In a sewing machine, the combination with a stitch-forming mechanism including a needle having oppositely directed stitchforming movements, means coperating with said needle to form stitches and means for advancing the fabric being acted on under said needle, of means operatively connected With the actuating mechanism of the sewing machine for giving to said needle stitch-forming movements in different planes including a pitman comprising a rigid portion and spiral springs operatively connected with its driving and driven elements, the resilient force of said s rings in the direction of their length e ecting a resistance greater than that offered by the power transmitted.

2. In a sewing machine, the combination with a stitch-forming' mechanism including a main-shaft, a needle having opposite di rected stitch-forming movements, means cooperating with said needle to form stitches and means for advancing the fabric being acted on under said needle, of elements for operatively connecting said main-shaft with said needle for giving to the latter stitchforming movements in different planes, said elements including a pitman resilient in the direction of its length and at any angle oblique to said direction, the resilient force of said pitman in the direction of its length eiecting a greater resistance than the power transmitted.

3. In a sewing machine, the combination with a stitch-formi1ig and cloth-feeding mechanism including a main-shaft, a needlebar operatively connected with said shaft and provided With a needle and means c0- operating with said needle to form stitches, of elements for operatively connecting said main-shaft with said needle for giving to the latter stitch-forming movements in different planes, said elements including a pitnian resilient in the direction of its length and at any angle oblique to such direction, the resilient force of said pitman in the direction of its length effecting a greater resistance than the power transmitted.

4. In a hemstitch sewing machine, a stitch-forming mechanism and fabric feeding mechanism, said stitch-forming mechanism including' a main-shaft provided with a gearmember, a 11eedlebar, a fabricpiercer, a tubular piercer carrying bar into which said needle-bar is located, a needle having oppositely directed stitch-forming movements carried by said needle-bar and connections between the latter and said mainshaft for giving the needle stitch-forming movements in different planes, said connections including a yoke j ournaled on the same axis as said needle-bar and provided with a guideway intermediate its. bearings in which track a lug carried by said needle-bar and an oscillating lever for giving the said yoke its oscillatory movements.

In testimony whereof I have signed my name to this specification in the presence of two subscribing witnesses.

CHARLES M. ABERCROMBIE.

Witnesses:

A. S. BUNNELL,

J. A. HAYWARD.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents, Washington, D. G. 

